The underbody shields minimize drag related to turbulence created by uneven surfaces on the bottom of the vehicle. "The 2012 Fusion had a nice set of shields on it, giving us some benefit, but we knew we had to go above and beyond, and we went after an excellent set of underbody shields," Park says. "They turn the underbody of the vehicle into a flat surface, so that instead of going under the vehicle and hitting components and creating drag, the air swoops past the components and exits in a nice pattern." Most vehicles have a small number of underbody shields, but typically components such as the exhaust, rear suspension components and the fuel tank hang down, creating barriers to airflow. For instance, the 2012 Fusion had just two underbody shields; the 2013 version will have close to a dozen.
A new feature on the 2013 Fusion is active grille shutters that are activated automatically at higher speeds to reduce drag. Automobile engines generate heat. Typically, the grille enables air to flow through the radiator to help cool the engine. A disadvantage is that the airflows into the engine compartment and creates drag as it leaves through the rear of the vehicle. "What we found is that we don't need all the capacity of the cooling system all of the time," Parks says. "At highway speed, we can close off a good percentage of the cooling path, because at that point we'd rather have the air go around or over the car and not create drag." "It's similar to the louvered blinds on a window," he says. "These are in front of the radiator. Under conditions discerned by the engine control unit, they can close when cooling is no longer needed to improve efficiency."